The present invention relates to elevators. It applies, in particular, to elevators having a shallow pit and/or a low overhead.
Elevators with a shallow pit and/or a low overhead are advantageous because of the reduced impact of their installation on the construction cost and because of their compatibility with severe architectural constraints.
Machine room-less elevators have their drive system, in particular their motor and brake, located inside the volume of the elevator shaft. Access to these parts, and to other components fitted in the shaft is required for maintenance or repair purposes. Standards such as EN81 require safety clearances at the top and at the bottom of the shaft so that a person can enter a safe working space to have access to the machines and shaft components. Such working space can be located in the upper part of the hoistway, with the operator standing on top of the car, or in the pit at the bottom of the shaft.
Safety measures to make sure that the minimum safety volume is always achieved in an inspection operation have been proposed. For example, the motor and the brake are deactivated to stop movement of the car if it is detected that the car is located out of a height range defined for inspection travel, the height range providing minimum working space at the top and/or bottom of the shaft to allow a mechanic to stand on top of the car or at the bottom of the pit and have access to various parts. It is also possible to take advantage of the safety brake usually present in the elevator structure to prevent the car from traveling at an excessive speed. In this case, the safety brake is triggered by a stop member located at a specified height in the shaft, the stop member being retracted during normal operation of the elevator to let the car reach the lowest and highest landing levels (see, e.g., US 2004/0222046 and WO 2006/035264).